Honda HRR GCV160 Hard to Start

[SpoolinV70]

I recently got my Honda HRR mower running, and all of a sudden, it stopped working again. The engine turned over just fine before, but now it hits a hard spot when pulling the cord. I already check the clearance on the magneto and the flywheel brake and they're fine. The issue is within the engine.
It is impossible to start it. When the spark plug is out it turns freely, but not with it in. When I pull the cord, it hits a very hard spot and it's not possible to overcome it to get the mower started.
I adjusted the valve clearance, as they were slightly out. After pulling the valve cover again, I noticed that the valves are out again. Clearance is way higher than it should be.
I think what is happening is that rocker arms are stripped on the threads, and the lifters are pushing through. I also noticed when I tighten the lock nut on the lifter, although not visually noticeable, it seems to skip back a few threads and the clearance is way higher than I set it.
Should I order new rocker arms and lifters, or just new rocker arms? Or is there something else I should check first?

 

[SpoolinV70]

Never mind that... I'm feeling very stupid right now.
It turns out I was turning the engine the wrong way to get it to what I thought was TDC on the compression stroke. After realizing my mistake, I promptly discovered the valve clearance was WAAAAY over what it is supposed to be.
I set the clearance correctly, replaced the spark plug, and turned the motor over a few times. It is MUCH smoother now with no violent stops. It took a couple revolutions to smooth out a little more, but I think that was just because the oil hadn't circulated. I RTV'd the valve cover and I'm about to torque the bolts down, and I'll start it up tomorrow to make sure it still runs...
I will update this thread if I come across any other problems.